The present disclosure relates to the generation of steam resulting from the combustion and processing of carbonaceous material for the generation of electricity and other uses.
Despite the serious problems caused by its use, coal is cheap and plentiful and will not be abandoned as an energy source any time soon. According to the Pew Center for Global Climate Change, coal use, primarily for the generation of electricity, now accounts for roughly 20 percent of global greenhouse gas emissions. Rising energy demand will continue to drive up coal consumption, particularly in countries with large reserves such as the United States, China and India. http://www.pewclimate.org/global-warming-basics/coalfacts.cfm.
Coal can provide usable energy at a cost of between $1 and $2 per MMBtu compared to $6 to $12 per MMBtu for oil and natural gas, and coal prices are relatively stable. At current consumption rates and with current technology and land-use restrictions, the U.S. coal reserves would last well over 250 years. Although coal is higher-polluting and more carbon-intensive than other energy alternatives, coal is so inexpensive that one can spend quite a bit on pollution control and still maintain coal's competitive position.
Coal plays a major role in meeting U.S. energy needs, and is likely to continue to do so in coming decades. About fifty percent of the electricity generated in the United States is from coal. U.S. coal-fired plants have over 300 GW of capacity, but approximately one-third of the U.S. coal-fired plants date from 1970 or earlier, and most of the rest from 1970-1989. Only twelve coal-fired plants have been built in the United States since 1990.
Greenhouse gas emissions from coal-fired power are significant and growing rapidly. The United States has been estimated to produce close to 2 billion tons of CO2 per year from coal-burning power plants. Greenhouse gas emissions from coal-fired electricity, now 27 percent of total U.S. emissions, are projected to grow by a third by 2025.